1. Field of the Invention
The invention relates to a plant for the pyrolysis of waste material containing hydrocarbons, especially waste material containing plastic and/or rubber wastes, including a pyrolysis reactor, and at least one cooling stage for hot pyrolysis gas produced in the pyrolysis reactor, at least the cooling stage immediately downstream of the pyrolysis reactor having a cooler with a downwardly-extending heat exchange channel for direct heat exchange between the hot pyrolysis gas and pyrolysis oil produced by condensation of pyrolysis gas.
2. Description of the Prior Art
In order to cool and partially condense hot pyrolysis gas in a pyrolysis plant, it is known from German Published, Prosecuted Application DE-AS 29 28 676 to directly contact the pyrolysis gas with sprayed-in pyrolysis oil in a cooling stage with a vertically extending heat exchange channel. In such a case, the pyrolysis oil which is sprayed is obtained by direct cooling in the cooling stage. During the cooling step, there is a risk of hot pyrolysis gas coming into contact with the cooler wall of the heat exchange channel, of constituents of the pyrolysis gas condensing, cracking and/or polymerizing in an undesirable manner and of solid or viscous reaction products, especially coke, soot or tars, depositing on the wall. In the prior art cooling stage, the deposition is greatly promoted by the spray directions of the spray nozzles which are horizontally aligned opposite one another and thus allow large regions of the inside wall to be subjected to the hot pyrolysis gas. In addition, there is also a large distance between the spray nozzles and the upper feed point of the hot pyrolysis gas, making further large wall areas available for condensation and/or cracking. Finally, the wall of the heat exchange channel must be formed of a material which withstands the hot pyrolysis gas at a temperature of from 400.degree. to 900.degree. Celsius. This increases the cost of the plant.